Horse Power and Torque

[StacytheBloke]

Quoting the auto math handbook (HP Books)

Drive wheel torque = flywheel torque x gear box ratio x diff ratio x transmission efficiency (around 0.85)

Wheel thrust is the thrust a tyre applys to the road.

Wheel thrust = drive wheel torque / wheel rolling radius

This can then gives a G'force value and g force we all agree increases with an increased rate of acceleration.

G force = wheel thrust/vehicle weight

Notice how in all these calcs for acceleration there is no mention of bhp. Torque wins races hence why a WRC evo or subaru will out accelerate a road going version which has a higher bhp value but a lower torque value even if the WRC car is ballasted to the same weight. We all know 800bhp is achievable in evos and imprexxies yet the wrc cars only pack sub 400bhp (i know restrictors have something to do with that) The mental tune caged and lightened 800 bhp cars would struggle to keep up in the acceleration stakes.

Torque does indeed win races where acceleration is king, less so in say indy oval or nascar racing

 

[rms]

Quoting the auto math handbook (HP Books)

Drive wheel torque = flywheel torque x gear box ratio x diff ratio x transmission efficiency (around 0.85)

Wheel thrust is the thrust a tyre applys to the road.

Wheel thrust = drive wheel torque / wheel rolling radius

This can then gives a G'force value and g force we all agree increases with an increased rate of acceleration.

G force = wheel thrust/vehicle weight

Notice how in all these calcs for acceleration there is no mention of bhp.

From none of the above can you derive acceleration !!!!!!!!

The following definitions are universally accepted in engineering

FORCE - a simple push/pull by direct contact or by no direct contact (magnetism,gravity) and is STATIC

WORK - in mechanics is the product of FORCE x DISTANCE and expressed by force and distance (lb/ft, Newton/metres) and is STATIC

TORQUE - is the measure of a FORCE to rotate a body about an axis, expressed as lb/ft, Newton/metres and is STATIC

POWER - in mechanics is the product of FORCE x DISTANCE divided by TIME. It is the measure of the amount of WORK in a given TIME.

VELOCITY - is the time-rate of change in distance MPH,KPH, ft/sec

ACCELERATION - is the time-rate of change of velocity and expressed in ft/sec/sec, mtrs/sec/sec, or as a percentage of gravity G's

FORCE, WORK and TORQUE are STATIC values.

POWER, VELOCITY and ACCELERATION are the application of the STATIC values in a given TIME.

If anyone requires further clarification please PM me.

 

[jibbby]

Fellas, I am sure you guys are more knowledgeable about the dynamics and mathematical equations in regards to horse power vs. Torque, and I am not questioning the reasoning behind it....

However, I go from my basic hit the throttle experience...My experience with torque is derived from the use of nitrous oxide... My N/A 1uz-fe dishes out a measly 210whp and 219 torque without the use of nitrous, then when using the juice the power numbers go to approx. 290whp and 500 ft pounds of torque...Now the 80whp increase is not going to make my car feel like it more then doubles in power it is the nearly 300 foot pounds of torque increase that gets my rears spinning out for nearly a full residential block... Night and day... Maybe my aggressive stall rate torque converter plays a part (gearing) but it it is the torque that makes all the difference in my car..

Now I've been in similar cars with 300whp and maybe as much as 350 torque and it's just not the same...Torque is huge, as shown in Diesel vehicles, Constuction machines, etc...

Maybe power is king but to me it's all about the Torque......